Muc-1, integrin, and osteopontin expression during the implantation cascade in sheep

Center for Animal Biotechnology and Genomics, Texas A&M University, College Station, TX 77843-2471, USA.
Biology of Reproduction (Impact Factor: 3.32). 10/2001; 65(3):820-8.
Source: PubMed


The extracellular matrix protein osteopontin (OPN) is a component of histotroph that increases in uterine flushings from pregnant ewes during the peri-implantation period and is localized on the apical surfaces of the uterine luminal epithelium (LE) and conceptus trophectoderm (Tr). The potential involvement of OPN in the implantation adhesion cascade in sheep was investigated by examining temporal, spatial, and potential functional relationships between OPN, Muc-1, and integrin subunits during the estrous cycle and early pregnancy. Immunoreactive Muc-1 was highly expressed at the apical surfaces of uterine luminal (LE) and glandular epithelium (GE) in both cycling and pregnant ewes but was decreased dramatically on LE by Day 9 and was nearly undetectable by Day 17 of pregnancy when intimate contact between LE and Tr begins. In contrast, integrin subunits αν, α4, α5, β1, β3, and β5 were constitutively expressed on conceptus Tr and at the apical surface of uterine LE and GE in both cyclic and early pregnant ewes. The apical expression of these subunits could contribute to the apical assembly of several OPN receptors including the ανβ3, ανβ1, α4β1, and α5β1 heterodimers on endometrial LE and GE, and conceptus Tr in sheep. Functional analysis of potential OPN interactions with conceptus and endometrial integrins was performed on LE and Tr cells in vitro using beads coated with OPN, poly-L-lysine, or recombinant OPN in which the Arg-Gly-Asp sequence was replaced with RGE or RAD. Transmembrane accumulation of talin or α-actinin at the apical surface of uterine LE and conceptus Tr cells in contact with OPN-coated beads revealed functional integrin activation and cytoskeletal reorganization in response to OPN binding. These results provide a physiological framework for the role of OPN, a potential mediator of implantation in sheep, as a bridge between integrin heterodimers expressed by Tr and uterine LE responsible for adhesion for initial conceptus attachment.

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    • "Placenta detailed information is available on the complex interplay of integrin subunits, Muc-1 and mediating matrix molecules like osteopontin (OPN) [3]. Molecules serving as potential inducers of such depolarization could be trophoblast products like pregnancy associated glycoproteins (PAG) [4] or IFN-tau, which is produced by uninucleate trophoblast in enlarging blastocysts and is believed to act as the maternal recognition signal in ruminants [5]. "
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    ABSTRACT: The feto-maternal interface during bovine implantation was studied in vivo and using three-dimensional bovine endometrial (BCECph) and trophoblast spheroids (CCS), each with underlying fibroblasts. The expression of ezrin and cytokeratin 18 (CK18) was analyzed via immunohistochemistry (IHC), RT-PCR and western blotting in bovine endometrium (GD 18-44) with in vivo (VIVO) and in vitro-produced embryos (VITRO). BCECph were stimulated with cotyledon-conditioned media (CCM) and analyzed by TEM/SEM and IHC. CCS were stained (IHC) for TGC markers, to test if spheroidal trophoblast cells had differentiated into TGC. At GD 20, caruncular epithelium (CE) and uterine glands (UG) showed a loss of cytosolic ezrin and CK18 followed by a complete loss of both proteins. At GD 35 both reappeared in CE and UG. The endometrial expression pattern did not differ between VIVO and VITRO. RT-PCR and western blotting confirmed the presence of ezrin and CK18. All spheroids had an outer polarized, cytokeratin and ezrin positive epithelium (CE or trophoblast) with apical microvilli. Stimulation of BCECph with CCM induced similar changes in ezrin expression as observed in endometrial tissue. However, no ultrastructural alterations were found by transmission electron microscopy. Absence of TGC-specific glycoproteins in CCS indicated that TGC differentiation was not induced by three-dimensional culture conditions. Ezrin and CK18 are downregulated during implantation in cattle. The expression changes represent a temporal depolarization, which could be important for an establishment of bovine pregnancy. Our in vitro experiments demonstrate that the trophoblast could contribute to this change in vivo. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Placenta 06/2015; 36(8). DOI:10.1016/j.placenta.2015.06.001 · 2.71 Impact Factor
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    • " disrupters block or modify uterine adenogenesis ; therefore , stromal cell - derived growth factors may exert effects only on uterine LE which is insufficient in its produc - tion of components of histotroph required for conceptus development . Down - regulation of PGR correlates with loss of MUC1 on uterine LE that interferes with implantation ( Johnson et al . , 2001 ) . Further , silencing expression of PGR in ovine uterine epithelia allows P4 to act via PGR - positive uterine stromal cells to induce Fig . 4 . Down - regulation of receptors for progesterone ( PGR ) is a common feature of pregnancy in mammals . It is required for down - regulation of expression of mucin 1 ( Muc - 1 ) which would oth"
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    ABSTRACT: Uterine adenogenesis, a unique post-natal event in mammals, is vulnerable to endocrine disruption by estrogens and progestins resulting in infertility or reduced prolificacy. The absence of uterine glands results in insufficient transport of nutrients into the uterine lumen to support conceptus development. Arginine, a component of histotroph, is substrate for production of nitric oxide, polyamines and agmatine and, with secreted phosphoprotein 1, it affects cytoskeletal organization of trophectoderm. Arginine is critical for development of the conceptus, pregnancy recognition signaling, implantation and placentation. Conceptuses of ungulates and cetaceans convert glucose to fructose which is metabolize via multiple pathways to support growth and development. However, high fructose corn syrup in soft drinks and foods may increase risks for metabolic disorders and increase insulin resistance in adults. Understanding endocrine disrupters and dietary substances, and novel pathways for nutrient metabolism during pregnancy can improve survival and growth, and prevent chronic metabolic diseases in offspring.
    Molecular and Cellular Endocrinology 09/2014; 398(1-2). DOI:10.1016/j.mce.2014.09.007 · 4.41 Impact Factor
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    • "The OPN protein is expressed at a high level in the uterine epithelium during the mid-secretory phase, in the decidua and in the cytotrophoblast in humans [14]. Studies in sheep and swine have indicated that OPN is involved in the interaction between uterine LE and the trophectoderm [15], [16]. In mice, OPN is expressed in the uterine glandular epithelium (GE) on day 4 [17] and in the immune cells surrounding the decidual cells during early pregnancy [18]. "
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    ABSTRACT: Embryo implantation into the maternal uterus is a decisive step for successful mammalian pregnancy. Osteopontin (OPN) is a member of the small integrin-binding ligand N-linked glycoprotein family and participates in cell adhesion and invasion. In this study, we showed that Opn mRNA levels are up-regulated in the mouse uterus on day 4 and at the implantation sites on days 5 and 8 of pregnancy. Immunohistochemistry localized the OPN protein to the glandular epithelium on day 4 and to the decidual zone on day 8 of pregnancy. OPN mRNA and proteins are induced by in vivo and in vitro decidualization. OPN expression in the endometrial stromal cells is regulated by progesterone, a key regulator during decidualization. As a secreted protein, the protein level of OPN in the uterine cavity is enriched on day 4, and in vitro embryo culturing has indicated that OPN can facilitate blastocyst hatching and adhesion. Knockdown of OPN attenuates the adhesion and invasion of blastocysts in mouse endometrial stromal cells by suppressing the expression and enzymatic activity of matrix metalloproteinase-9 in the trophoblast. Our data indicated that OPN expression in the mouse uterus during early pregnancy is essential for blastocyst hatching and adhesion and that the knockdown of OPN in mouse endometrial stroma cells could lead to a restrained in vitro trophoblast invasion.
    PLoS ONE 08/2014; 9(8):e104955. DOI:10.1371/journal.pone.0104955 · 3.23 Impact Factor
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